Class D Amp vs just an Amp
1000 Watt CAFz'r
Joined: May 2004
Posts: 1,145
dude, seroiusly man, no its the clipping. I've stuffed 1300 WRMS into my 400 watt Vifa without a single problem, no problem at all. It was using a Lanzar monoblock rack-mount 3k RMS amp. The coil didn't heat up at all, even though I was stuffing 1300 into it for about 10 minutes. Neither did the sub bottom out once. always good controlled awesome power. what is thermal rating? I've yet to see a non- Pro audio sub with thermal rating. I've Fried both my Kove Z-15, and my Ground Zero Radioactive 15, all because of this one (I wont mention the company) but this one *garbage* amp company had an amp that didn't at all perform like it supposed to. yes the amp clipped BIG TIME, thats why I quickly lost $1k worth of subs. with about 2 hours playing time between the two. Now I have a decent ZR240, it still clips a little when I pound it, but I have no coils heating up, or bottoming out or other problems caused by amp clipping. ITs all about good clean power man. Thats why I love Kicker, and all these other good companies like Zapco and MMATS, RipRock etc. You just cant go wrong.... IMO.
[ February 12, 2005, 08:12 PM: Message edited by: SPL donut ... ]
[ February 12, 2005, 08:12 PM: Message edited by: SPL donut ... ]
So you think the best of the best amps wont clipp?
The amp is not clipping on its own my friend.
Youre making it clip,youre forcing it to try to put out more than it was made to,whether it be youre ****ty jenson or you mediocre kicker.
You guys should be a team,You ask stupid questions ......he will give stupid answers ,lol
The amp is not clipping on its own my friend.
Youre making it clip,youre forcing it to try to put out more than it was made to,whether it be youre ****ty jenson or you mediocre kicker.
You guys should be a team,You ask stupid questions ......he will give stupid answers ,lol
500 Watt CAFz'r
Joined: Dec 2000
Posts: 952
The best way to find a difference between a Class "D" and non-Class "D" is to actually listen to the difference between various classifications of amplifiers.
In essence it does have to do with the way the output transistors deal with a given sine waye, and how that sine wave is broken up, how fast the transistors switch. In Class "D" the output transistors switch fast and more frequently than some other classes, meaning there are more transistors per channel. The resulting sound quality may be described as very fast and somewhat shrill on attack, but shallow in depth of deep bass response.
As for the doubling of power, yes it's a good idea to have more power to allow the speaker to reproduce dynamic passages without showing the strain on the amplifier when you need to listen at moderatly loud levels.
No different that having an 8Cyl. Vs. 4Cyl. while passing a semi-trailer and travelling at 140KMH, and having to speed up to make a quick passing manoever.
Here is a description of various classifications of amplifiers out there, you may find it interesting, and I hope it helps. (the term "Devices" referrs to the output transistors)
Class A operation is where both devices conduct continuously for the entire cycle of signal swing, or the bias current flows in the output devices at all times. The key ingredient of class A operation is that both devices are always on. There is no condition where one or the other is turned off. Because of this, class A amplifiers in reality are not complementary designs. They are single-ended designs with only one type polarity output devices. They may have "bottom side" transistors but these are operated as fixed current sources, not amplifying devices. Consequently class A is the most inefficient of all power amplifier designs, averaging only around 20% (meaning you draw about 5 times as much power from the source as you deliver to the load!) Thus class A amplifiers are large, heavy and run very hot. All this is due to the amplifier constantly operating at full power. The positive effect of all this is that class A designs are inherently the most linear, with the least amount of distortion. [Much mystique and confusion surrounds the term class A. Many mistakenly think it means circuitry comprised of discrete components (as opposed to integrated circuits). Such is not the case. A great many integrated circuits incorporate class A designs, while just as many discrete component circuits do not use class A designs.]
Class B operation is the opposite of class A. Both output devices are never allowed to be on at the same time, or the bias is set so that current flow in a specific output device is zero when not stimulated with an input signal, i.e., the current in a specific output flows for one half cycle. Thus each output device is on for exactly one half of a complete sinusoidal signal cycle. Due to this operation, class B designs show high efficiency but poor linearity around the crossover region. This is d ue to the time it takes to turn one device off and the other device on, which translates into extreme crossover distortion. Thus restricting class B designs to power consumption critical applications, e.g., battery operated equipment, such as 2-way radio and other communications audio.
Class AB operation is the intermediate case. Here both devices are allowed to be on at the same time (like in class A), but just barely. The output bias is set so that current flows in a specific output device appreciably more than a half cycle but less than the entire cycle. That is, only a small amount of current is allowed to flow through both devices, unlike the complete load current of class A designs, but enough to keep each device operating so they respond instantly to input voltage demand s. Thus the inherent non-linearity of class B designs is eliminated, without the gross inefficiencies of the class A design. It is this combination of good efficiency (around 50%) with excellent linearity that makes class AB the most popular audio amplifier design.
Class AB plus B design involves two pairs of output devices: one pair operates class AB while the other (slave) pair operates class B.
Class C use is restricted to the broadcast industry for radio frequency (RF) transmission. Its operation is characterized by turning on one device at a time for less than one half cycle. In essence, each output device is pulsed-on for some percentage of the half cycle, instead of operating continuously for the entire half cycle. This makes for an extremely efficient design capable of enormous output power. It is the magic of RF tuned circuits (flywheel effect) that overcomes the distortion create d by class C pulsed operation.
Class D operation is switching, hence the term switching power amplifier. Here the output devices are rapidly switched on and off at least twice for each cycle (Sampling Theorem). Theoretically since the output devices are either completely on or completely off they do not dissipate any power. If a device is on there is a large amount of current flowing through it, but all the voltage is across the load, so the power dissipated by the device is zero (found by multiplying the voltage across the device [zero] times the current flowing through the device [big], so 0 x big = 0); and when the device is off, the voltage is large, but the current is zero so you get the same answer. Consequently class D operation is theoretically 100% efficient, but this requires zero on-impedance switches with infinitely fast switching times -- a product we're still waiting for; meanwhile designs do exist with true efficiencies approaching 90%. [Historical note: the original use of the term "Class D" referred to switching amplifiers that employed a resonant circuit at the output to remove the harmonics of the switching frequency. Todays use is much closer to the original "Class S" designs.
Class E operation involves amplifiers designed for rectangular input pulses, not sinusoidal audio waveforms. The output load is a tuned circuit, with the output voltage resembling a damped single pulse. Normally Class E employs a single transistor driven to act as a switch.
The following terms, while generally agreed upon, are not considered "official" classifications
Class F Also known by such terms as "biharmonic," "polyharmonic," "Class DC," "single-ended Class D," "High-efficiency Class C," and "multiresonator." Another example of a tuned power amplifier, whereby the load is a tuned resonant circuit. One of the differences here is the circuit is tuned for one or more harmonic frequencies as well as the carrier frequency.
Class G operation involves changing the power supply voltage from a lower level to a higher level when larger output swings are required. There have been several ways to do this. The simplest involves a single class AB output stage that is connected to two power supply rails by a diode, or a transistor switch. The design is such that for most musical program material, the output stage is connected to the lower supply voltage, and automatically switches to the higher rails for large signal peaks [ thus the nickname rail-switcher]. Another approach uses two class AB output stages, each connected to a different power supply voltage, with the magnitude of the input signal determining the signal path. Using two power supplies improves efficiency enough to allow significantly more power for a given size and weight. Class G is becoming common for pro audio designs. [Historical note: HITACHI is credited with pioneering class G designs with their 1977 Dynaharmony HMA 8300 power amplifier]. *(And the introduction of the M.O.S.F.E.T transistor, added by E.C.)
Class H operation takes the class G design one step further and actually modulates the higher power supply voltage by the input signal. This allows the power supply to track the audio input and provide just enough voltage for optimum operation of the output devices [thus the nickname rail-tracker or tracking power amplifier]. The efficiency of class H is comparable to class G designs. [Historical note: Soundcraftsmen is credited with pioneering class H designs with their 1977 Vari-proportional MA5002 power amplifier.]
Class S First invented in 1932, this technique is used for both amplification and amplitude modulation. Similar to Class D except the rectangular PWM ( Pulse Width Modulation ) voltage waveform is applied to a low-pass filter that allows only the slowly varying dc or average voltage component to appear across the load. Essentially this is what is termed "Class D" today.
[ February 12, 2005, 09:11 PM: Message edited by: Eli47 ]
In essence it does have to do with the way the output transistors deal with a given sine waye, and how that sine wave is broken up, how fast the transistors switch. In Class "D" the output transistors switch fast and more frequently than some other classes, meaning there are more transistors per channel. The resulting sound quality may be described as very fast and somewhat shrill on attack, but shallow in depth of deep bass response.
As for the doubling of power, yes it's a good idea to have more power to allow the speaker to reproduce dynamic passages without showing the strain on the amplifier when you need to listen at moderatly loud levels.
No different that having an 8Cyl. Vs. 4Cyl. while passing a semi-trailer and travelling at 140KMH, and having to speed up to make a quick passing manoever.
Here is a description of various classifications of amplifiers out there, you may find it interesting, and I hope it helps. (the term "Devices" referrs to the output transistors)
Class A operation is where both devices conduct continuously for the entire cycle of signal swing, or the bias current flows in the output devices at all times. The key ingredient of class A operation is that both devices are always on. There is no condition where one or the other is turned off. Because of this, class A amplifiers in reality are not complementary designs. They are single-ended designs with only one type polarity output devices. They may have "bottom side" transistors but these are operated as fixed current sources, not amplifying devices. Consequently class A is the most inefficient of all power amplifier designs, averaging only around 20% (meaning you draw about 5 times as much power from the source as you deliver to the load!) Thus class A amplifiers are large, heavy and run very hot. All this is due to the amplifier constantly operating at full power. The positive effect of all this is that class A designs are inherently the most linear, with the least amount of distortion. [Much mystique and confusion surrounds the term class A. Many mistakenly think it means circuitry comprised of discrete components (as opposed to integrated circuits). Such is not the case. A great many integrated circuits incorporate class A designs, while just as many discrete component circuits do not use class A designs.]
Class B operation is the opposite of class A. Both output devices are never allowed to be on at the same time, or the bias is set so that current flow in a specific output device is zero when not stimulated with an input signal, i.e., the current in a specific output flows for one half cycle. Thus each output device is on for exactly one half of a complete sinusoidal signal cycle. Due to this operation, class B designs show high efficiency but poor linearity around the crossover region. This is d ue to the time it takes to turn one device off and the other device on, which translates into extreme crossover distortion. Thus restricting class B designs to power consumption critical applications, e.g., battery operated equipment, such as 2-way radio and other communications audio.
Class AB operation is the intermediate case. Here both devices are allowed to be on at the same time (like in class A), but just barely. The output bias is set so that current flows in a specific output device appreciably more than a half cycle but less than the entire cycle. That is, only a small amount of current is allowed to flow through both devices, unlike the complete load current of class A designs, but enough to keep each device operating so they respond instantly to input voltage demand s. Thus the inherent non-linearity of class B designs is eliminated, without the gross inefficiencies of the class A design. It is this combination of good efficiency (around 50%) with excellent linearity that makes class AB the most popular audio amplifier design.
Class AB plus B design involves two pairs of output devices: one pair operates class AB while the other (slave) pair operates class B.
Class C use is restricted to the broadcast industry for radio frequency (RF) transmission. Its operation is characterized by turning on one device at a time for less than one half cycle. In essence, each output device is pulsed-on for some percentage of the half cycle, instead of operating continuously for the entire half cycle. This makes for an extremely efficient design capable of enormous output power. It is the magic of RF tuned circuits (flywheel effect) that overcomes the distortion create d by class C pulsed operation.
Class D operation is switching, hence the term switching power amplifier. Here the output devices are rapidly switched on and off at least twice for each cycle (Sampling Theorem). Theoretically since the output devices are either completely on or completely off they do not dissipate any power. If a device is on there is a large amount of current flowing through it, but all the voltage is across the load, so the power dissipated by the device is zero (found by multiplying the voltage across the device [zero] times the current flowing through the device [big], so 0 x big = 0); and when the device is off, the voltage is large, but the current is zero so you get the same answer. Consequently class D operation is theoretically 100% efficient, but this requires zero on-impedance switches with infinitely fast switching times -- a product we're still waiting for; meanwhile designs do exist with true efficiencies approaching 90%. [Historical note: the original use of the term "Class D" referred to switching amplifiers that employed a resonant circuit at the output to remove the harmonics of the switching frequency. Todays use is much closer to the original "Class S" designs.
Class E operation involves amplifiers designed for rectangular input pulses, not sinusoidal audio waveforms. The output load is a tuned circuit, with the output voltage resembling a damped single pulse. Normally Class E employs a single transistor driven to act as a switch.
The following terms, while generally agreed upon, are not considered "official" classifications
Class F Also known by such terms as "biharmonic," "polyharmonic," "Class DC," "single-ended Class D," "High-efficiency Class C," and "multiresonator." Another example of a tuned power amplifier, whereby the load is a tuned resonant circuit. One of the differences here is the circuit is tuned for one or more harmonic frequencies as well as the carrier frequency.
Class G operation involves changing the power supply voltage from a lower level to a higher level when larger output swings are required. There have been several ways to do this. The simplest involves a single class AB output stage that is connected to two power supply rails by a diode, or a transistor switch. The design is such that for most musical program material, the output stage is connected to the lower supply voltage, and automatically switches to the higher rails for large signal peaks [ thus the nickname rail-switcher]. Another approach uses two class AB output stages, each connected to a different power supply voltage, with the magnitude of the input signal determining the signal path. Using two power supplies improves efficiency enough to allow significantly more power for a given size and weight. Class G is becoming common for pro audio designs. [Historical note: HITACHI is credited with pioneering class G designs with their 1977 Dynaharmony HMA 8300 power amplifier]. *(And the introduction of the M.O.S.F.E.T transistor, added by E.C.)
Class H operation takes the class G design one step further and actually modulates the higher power supply voltage by the input signal. This allows the power supply to track the audio input and provide just enough voltage for optimum operation of the output devices [thus the nickname rail-tracker or tracking power amplifier]. The efficiency of class H is comparable to class G designs. [Historical note: Soundcraftsmen is credited with pioneering class H designs with their 1977 Vari-proportional MA5002 power amplifier.]
Class S First invented in 1932, this technique is used for both amplification and amplitude modulation. Similar to Class D except the rectangular PWM ( Pulse Width Modulation ) voltage waveform is applied to a low-pass filter that allows only the slowly varying dc or average voltage component to appear across the load. Essentially this is what is termed "Class D" today.
[ February 12, 2005, 09:11 PM: Message edited by: Eli47 ]
1000 Watt CAFz'r
Joined: May 2004
Posts: 1,145
uh,...... Kickerolds, I dont really consider a Kicker Zr series Mediocre. I consider that pretty frickin' high end. I really dont apologize for considering an amp "high end" that is so called "240 watts RMS", dishing out 550 watts RMS like it honestly does. The low end amp I was talking about is not my Jensen. It was my Ultra-linear UL1500X. with 4 40amp fuses, you'd think it has *****. it supposed to put out 600 watts RMS at 2 ohms. Well, I had a 150 watts RMS panasonic amp, and its funny how simular 150 were, to the so-called 600 RMS. the GZ radioactive was 500 watts RMS. with dual four ohm coils, both in parallel. The GZ sub should have been a good match for the UL amp. THe UL amp was I think 300 RMS at 4 ohms, 600 RMS at 2, and 1500 RMS at 1 ohm. yet I dont know exactly how much it was putting out since I never bench tested it, but it DEFINATELY wasn't 600 RMS. thats for damn sure. 
everybody on this board says its actually a good amp, and "Juggernaut Kia Sportage" uses the same amp, and USED the same amp to drive his MMATS Jugger 15 to 141 dbs at the Calgary test and tune. So maybe my amp was just garbage, but mine did not perform at all to the specs. I was really really upset. VERY pissed off, I was honestly going to use that amp as a frisbee, and have an intense game using it with a brick wall, I didn't I sold it for what I paid for it, but I sure was tempted to since i needed a little stress relief. Other people like UL, I detest it, and will never buy a UL for as long as I live unless they do a massive turnaround IMO. Some people have an awesome ear for hearing amp clipping. I dont, yet I still heard just how badly that P.O.S. UL was clipping to the subs I turned it way down, even though it still fried the Kove. The Kove was a 4 ohm sub, so I thought, if I hook up the 2 ohm GZ to the monoblock, I should be able to drive it harder, without any probs... WRONG!!! IM still really pissed. I fried two nice subs, which would have served great in competing, but there both TRASHED now, with big ir-repairable problems because of that. no crap that the high end amps clip, but at least they dont clip in a way that ruins subs in about 30 minutes flat. And they would at least have honest power ratings. I was really annoyed by how badly I was mis-lead. I had a cap, and hooked it up right. RCA voltage was ample, since I was using a PLD1. So what gives? Frick I hate UL
[ February 12, 2005, 10:12 PM: Message edited by: SPL donut ... ]
everybody on this board says its actually a good amp, and "Juggernaut Kia Sportage" uses the same amp, and USED the same amp to drive his MMATS Jugger 15 to 141 dbs at the Calgary test and tune. So maybe my amp was just garbage, but mine did not perform at all to the specs. I was really really upset. VERY pissed off, I was honestly going to use that amp as a frisbee, and have an intense game using it with a brick wall, I didn't I sold it for what I paid for it, but I sure was tempted to since i needed a little stress relief. Other people like UL, I detest it, and will never buy a UL for as long as I live unless they do a massive turnaround IMO. Some people have an awesome ear for hearing amp clipping. I dont, yet I still heard just how badly that P.O.S. UL was clipping to the subs I turned it way down, even though it still fried the Kove. The Kove was a 4 ohm sub, so I thought, if I hook up the 2 ohm GZ to the monoblock, I should be able to drive it harder, without any probs... WRONG!!! IM still really pissed. I fried two nice subs, which would have served great in competing, but there both TRASHED now, with big ir-repairable problems because of that. no crap that the high end amps clip, but at least they dont clip in a way that ruins subs in about 30 minutes flat. And they would at least have honest power ratings. I was really annoyed by how badly I was mis-lead. I had a cap, and hooked it up right. RCA voltage was ample, since I was using a PLD1. So what gives? Frick I hate UL[ February 12, 2005, 10:12 PM: Message edited by: SPL donut ... ]
